. >> the older brother, tamerlan was in russia in 2012. >> yes. >> six months. relatively recently. who did he meet with, what did he learn. what happened when they came back here. the investigation will take place here, was there anyone else here or any other aspects of the case that will help figure out the whys and hows that are important to us and of course abroad. there's a huge focus on both those parts, and it actually began wednesday when they were able to identify who the brothers were. >> it is impossible to think the older brother spent six months in russia and that had nothing to do with this. >> right. right now if you're looking at it from the facts that are known right now, maybe those six months did radicalize him and he learned techniques to come here. but i have been through enough cases, know enough about these cases that i am cautious about sort of looking at what we know now, saying that was the moment. we learned so much about other terrorists or sociopaths weeks or months later. we spoke about columbine, everything we thought about the columbine killers, not t